Funds from this Major Research Instrumentation (MRI) Program grant will support acquisition of four trailer mounted x-band polarimetric/Doppler radar systems by the Department of Civil and Environmental Engineering at the University of Iowa. The dual polarization radar design will allow for high spatial (1.5 deg beamwidth or ca. 250 m2 pixels at 10 km range) and temporal (ca. 1-2 minute scan times) remote sensing of rainfall distribution/rate, the 3-D wind field and to discriminate between rainfall, hail and snow over regions of 10-30 km2. Four complete custom-built mobile x-band (3 cm wavelength) radar systems will be built by ProSensing Inc. The systems will include the 6 ft. diameter radar antennae and elevation and azimuth variable pedestals. These systems will be mounted on truck trailers equipped with hydraulic leveling systems and on board 120 VAC generators. The mobile radar network will support meteorological and hydrologic research requiring high resolution observations of precipitation variability within regional storm cells. Research on multiple fronts of current interest in meteorology and hydrology will benefit from the proposed radar network including: 1) fundamental studies of uncertainty in radar measurement of rainfall parameters in gauged basins; 2) multi-radar and LiDAR imaging of rainfall events to study non-linear scaling effects between the range of the national NEXRAD (Next Generation Radar) s-band network (avg 4 km2 pixel resolution, maximum range of reflectivity ~ 230 km) and elastic scanning LiDAR (meter scale pixel resolution; range = 1-2 km); 3) studies of the effects of urbanization on meteorological and hydrologic processes; 4) flood prediction in ungauged basins; and 5) soil erosion processes. A better understanding of the relationships between storm events and hydrologic system dynamics of watersheds have clear societal relevance for water and soil resources management and hazards mitigation. The mobile radar network will facilitate collaborative research across the disciplines of meteorology and watershed hydrology and the equipment will be made available to external users. Data acquired will be wirelessly transmitted in real-time and will ultimately be made available for community access. Students will be engaged in the use and development of the radar system through the creation of courses in remote sensing and radar applications in both the departments of Civil Engineering and Electrical and Computer Engineering. The PI's are active in the University of Iowa Alliance for Graduate Education and Professoriate (AGEP) program for which the primary goal is to significantly increase the number of PhD degrees awarded to underrepresented U.S. minority students in science, technology, engineering, and mathematics. AGEP supports summer internships for students to provide them with hands-on research experiences.